Baza's suggestion is a good one, and not an old wive's tale.
When you first let the cat out, its instinct is to go racing off exploring, and, if it goes to far, it may well try to find its way to its old home, rather than the new one..
Putting butter on the cat's feet causes it to keep pausing to lick the butter off, which give it time to become familiar with its new surroundings.
My wife and I have been involved with cat rescue for 15 years, and have found this to be very effective.